I do think reading one character at a time is your best bet

It's generally poor form and very slow to read one char at a time with sysread(); it's unbuffered, as is C's read(), so you're making a system call per character. Ouch. If you ask for 1024 bytes and only one is available, it will be returned in $buf, sysread returning the number of chars actually read. For example: 

my $buf; my $nread;
open(my $filehandle, '<', 'f.tmp') or die "error open: $!";
while ($nread = sysread($filehandle, $buf, 1024)) {
    print "nread=$nread buf='$buf'\n";
}

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To illustrate my point, this program: 

use strict;
my $buf; my $nread;
open(my $filehandle, '<', 'f.tmp') or die "error open f.tmp: $!";
binmode($filehandle);
open(my $fhout, '>', 'g.tmp') or die "error open g.tmp: $!";
binmode($fhout);
while ($nread = sysread($filehandle, $buf, 1)) {
    print $fhout $buf;
}
close($filehandle); close($fhout);

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takes 27 seconds to copy file f.tmp to g.tmp, where f.tmp is perl-5.8.6.tar.gz (about 12 MB). If you simply change: 
sysread($filehandle, $buf, 1)

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above to: 
sysread($filehandle, $buf, 1024)

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the time reduces to 0.2 seconds.

In reply to Re^2: unbuffered read from socket by eyepopslikeamosquito
in thread unbuffered read from socket by Forsaken

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